The invention relates a method of determining database entries of a database by means of an automatic dialog system.
To guarantee automatic operation of the dialog system, usually an automatic speech recognition device is used which accesses a lexicon with lexicon entries (vocabulary of the speech recognition device) and works on the basis of Hidden Markov Models. The lexicon entries contain acoustic references for the speech recognition device which are compared with a speech input in a speech recognition procedure. The acoustic references represent for example sequences of phonemes. The method according to the invention for example relates to a “Yellow Pages” service. Using such a service each user can gain information on possible suppliers of a required sector for example doctors, tradesmen or other companies, but also public installations such as police stations, swimming pools, schools etc. Such sector information systems via telephone i.e. in the form of specialist telephone information are best known. In addition, there are already such information systems in data networks for example the internet or intranet. The terminal, depending on the type of information system, is either a phone, a mobile phone, a computer or an organizer etc. with a corresponding telephone function or, if an information system in a pure data network is used, PCs or organizers or mobile phones with the corresponding access facilities to the network concerned, for example WAP mobiles. The search parameters are various search criteria e.g. the sector, specialist field or location, or the associated search concepts of e.g. “doctors”, or “homeopathy” or “Munich”. The subscriber data may be, for example, the telephone number, the address or other information which enables the user to contact or reach the supplier subscribing to the information system i.e. included in the database of the information system. In known systems a lexicon is used for certain categories of speech inputs for example input of a sector, which lexicon is tailored to this demand on the speech recognition system in order to limit computing cost. Here the problem arises that the database search then performed for the speech recognition result concerned can find no associated database entry which can be output to the user.